As noted, using the term "incest" to describe this situation is, ah, problematic. At least in an era where web search is a big thing, and the language used at work needs to be family-friendly.
Vague memory is that I've heard the phrase "Siamese objects" used to describe this situation, or similar ones.
Vague memory is that I've heard the phrase "Siamese objects" used to describe this situation, or similar ones.